Although nephelometer instruments for measuring turbidity of liquids have been commercially available for many years, such instruments have been somewhat limited in their ability to measure turbidity of highly-turbid liquids. As the turbidity of a liquid increases, light has a more difficult time passing through the liquid. When the turbidity is too high, enough light cannot pass through to enable an accurate measurement of turbidity to be made. Errors in measurement therefore increase. Consequently, in order to measure highly-turbid liquids, it has been necessary to first dilute the highly-turbid liquid and then measure the turbidity of the diluted sample. The highest level of turbidity measurement which is possible with existing laboratory instruments is about 2000 NTU. Although a highly-turbid liquid sample may be diluted and then measured using existing instruments, this requires that the technician be very careful and accurate in making the dilution. Also, diluting the sample requires extra time and equipment and can physically change the sample. Thus, diluting the sample is not a preferred procedure.
Another limitation of commercially-available nephelo-meters is that they are not capable of measuring color in a liquid. The measurement of color in water is especially important, for example, in potable water. Further, measurement of color in a liquid is important in various industrial processes.
There has not heretofore been provided an improved nephelometer instrument having the advantages and features described herein.